An apparatus consisting of check valves (1, 2, 3) and one or more pressure tanks (4) plumbed into a water service line to provide a method of storing, reserving and delivering said stored water through the water service line to both the water user and the water supply. This method and apparatus can be used for emergency water supply by the water user or reduce water peak demand challenges caused by fluctuating water pressure if used extensively throughout a water supply system. This method and apparatus can create individual water storage collectives that can share water between users.